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Exploring stable cycling electrode materials with high energy and power density is the key to accelerating the development and application of supercapacitors. Ti3 C2 Tx , which is the most investigated member of the family of two-dimensional layered transition-metal carbides, has attracted considerable attention, owing to its unique two-dimensional morphology, large interlayer spacing, outstanding metallic conductivity, abundant chemical surface, and ultrahigh volumetric capacitance. However, the inherent restacking tendency of ultrathin Ti3 C2 Tx sheets hinder its practical application. In this review, the synthetic methods and charge-storage mechanisms of Ti3 C2 Tx are stressed to provide clues for improving its electrochemical performance. Functionalization, including architectural construction, hybridization, and surface modification of the Ti3 C2 Tx sheets, to circumvent difficulties and application in supercapacitors is then summarized. Accordingly, the aim is to highlight the opportunities and challenges for Ti3 C2 Tx -based materials in practical applications in supercapacitors.

Lithium–sulfur batteries are the most promising next-generation power source thanks to their extremely high theoretical capacity. However, the uncontrollable lithium dendrite growth and side reactions between the polysulfides and electrolyte for the Li metal anode result in a short lifespan, rapid capacity decay, low Coulombic efficiency, and safety concerns, impeding their practical development. In this work, a novel dual-layered artificial SEI on the Li metal anode is reported, which consists of organic lithiated Nafion on the top and inorganic LixSiSy on the bottom. The flexible Nafion layer can not only maintain the structural integrity of the SEI, but also hinder the side reactions between soluble polysulfides and the lithium anode, while the rigid inorganic layer is beneficial for diffusion of Li ions within it and suppression of Li dendrite growth. Accordingly, the protected Li electrode can steadily withstand successive Li plating/stripping processes for over 1400 h at a current density of 1 mA cm−2. Li–S batteries with a LixSiSy/Nafion film coated Li anode exhibit better cycling stability (783 mA h g−1 after 300 cycles at 0.5C) and higher rate performance (789 mA h g−1 at 2.0C) than those with a bare Li anode. This work highlights the significance of rational manipulation of the interfacial properties of a working Li metal anode and provides fresh insights into achieving dendrite-free Li deposition behaviors and high-cyclability Li–S batteries.

Lithium–sulfur (Li–S) batteries have attracted much attention due to their high theoretical energy density, environmental friendliness, and low cost. However, the practical application of Li–S batteries is impeded by a severe shuttle effect. Using polar and conductive materials to prepare a modified separator as the second collector is an effective strategy to solve the shuttle effect. Herein, a Ti3C2Tx–PEDOT:PSS hybrid for modifying PP separators is successfully fabricated. In this hybrid, PEDOT:PSS can effectively prevent Ti3C2Tx nanosheets from restacking and enhance the electrical conductivity of Li–S batteries, thereby promoting fast Li+/electron transport and improving the sulfur utilization. Meanwhile, the introduction of Ti3C2Tx–PEDOT:PSS makes Ti3C2Tx nanosheets effectively anchor polysulfide, thus inhibiting the shuttle effect. As a result, Li–S cells with Ti3C2Tx–PEDOT:PSS modified-separators exhibit superior performances, including a high discharge capacity of 1241.4 mA h g−1 at 0.2C, a long cycling stability, and a low decay rate of 0.030% per cycle at 0.5C for 1000 cycles.

Various forms of energy utilization have received a great deal of attention due to excessive fossil fuel consumption and related environmental issues. Electromagnetic energy, considered to be a widespread energy source, can be converted into heat energy and power energy to relieve energy pressure. Herein, we propose a general strategy to fabricate N-doped carbon nanotube/reduced graphene oxide aerogels consisting of metal@graphene core–shell nanoparticles and interconnected N-doped carbon nanotubes. Through this strategy, single-metal (Fe, Co and Ni) and bimetal (CoNi and CoFe)-based aerogels can be successfully fabricated. The as-synthesized aerogels have a density as low as 0.0109 g cm−3. The optimized aerogel displays excellent electromagnetic wave absorption properties when the filler ratio is only 8 wt%. Furthermore, we elucidate the potential of the aerogels in the conversion and utilization of electromagnetic energy. The experimental results demonstrate that the maximal conversion efficiency of the electromagnetic energy is up to 24.56% upon utilization of the optimized aerogel as an absorber. The heat energy converted from electromagnetic energy has potential applications in powering low-power electric devices. Our strategy opens up a possible way to utilize “waste” electromagnetic energy.

The efficiency of hydrogen production through water splitting is limited by the slow kinetics of the oxygen evolution reaction (OER). Although transition bimetal catalysts have advantages for OER, which of the metal plays a dominant role is still not clearly identified. Here, we synthesized a series of crystal (NixCo1−x)2B catalysts via a simple ball-milling method. Among these catalysts, (Ni0.75Co0.25)2B exhibits the best OER activity with a low overpotential of 224 mV at 10 mA cm−2 in a 1 M KOH solution as well as robust stability, which is superior to that of the benchmark IrO2 catalyst. More importantly, the chemical origins of these catalysts have been successfully identified via CV cycling on hydrophobic and hydrophilic electrodes. We found that Co sites served as both the adsorption centers of OH* intermediates and active centers for OER, while Ni sites facilitated the key conversion of Co2+ to Co3+ during OER through CV cycling. The findings are well supported by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) data. Our results open a reasonable strategy for high-performance OER catalysts.

Lithium-sulfur (Li-S) batteries have the potential to become the future energy storage system, yet they are plagued by sluggish redox kinetics. Therefore, enhancing the redox kinetics of polysulfides is key for the development of high-energy density and long-life Li-S batteries. Herein, a Ketjen Black (KB)/V

The practical application of Zn-metal anodes (ZMAs) is mainly impeded by the limited lifespan and low Coulombic efficiency (CE) resulting from the Zn dendrite growth and side reactions. Herein, a 3D multifunctional host consisting of N-doped carbon fibers embedded with Cu nanoboxes (denoted as Cu NBs@NCFs) is rationally designed and developed for stable ZMAs. The 3D macroporous configuration and hollow structure can lower the local current density and alleviate the large volume change during the repeated cycling processes. Furthermore, zincophilic Cu and in-situ-formed Cu-Zn alloy can act as homogeneous nucleation sites to minimize the Zn nucleation overpotential, further guiding uniform and dense Zn deposition. As a result, this Cu NBs@NCFs host exhibits high CE of Zn plating/stripping for 1000 cycles. The Cu NBs@NCFs-Zn electrode shows low voltage hysteresis and prolonged cycling life (450 h) with dendrite-free behaviors. As a proof-of-concept demonstration, a Zn-ion full cell is fabricated based on this Cu NBs@NCFs-Zn anode, which demonstrates decent rate capability and improved cycling performance. Ministry of Education (MOE) Submitted/Accepted version X.W.L. acknowledges the funding support from the Ministry of Education of Singapore through the Academic Research Fund (AcRF) Tier-1 grant (RG3/20) and Tier-2 grant (MOE2019-T2-2-049).

Hollow carbon spheres are potential candidates for lightweight microwave absorbers. However, the skin effect of pure carbon-based materials frequently induces a terrible impedance mismatching issue. Herein, small-sized NiO/Ni particles with heterojunctions on the N-doped hollow carbon spheres (NHCS@NiO/Ni) are constructed using SiO

Three-dimensional (3D) graphene-based structures have attracted much attention due to their unique physicochemical properties and potential applications in various fields. In this work, we develop a facile strategy for growing Co and Zn-contained nitrogen-doped carbon nanotubes on the graphene sheets for the absorption of electromagnetic wave (EMW). The as-fabricated 3D structures with a larger surface area have high electrical conductivities, abundant defects, numerous interfaces and porous feature, endowing them to excellent EMW absorption performance. The minimal reflection loss and efficient absorption bandwidth of the optimized 3D structure can reach to −47.31 dB and 4.01 GHz at a low thickness of merely 1.5 mm, respectively. Even at the thickness of 1.2–1.5 mm, the minimal reflection losses are less than −10 dB. Furthermore, the filler mass loading of the 3D structures is only 6 wt%, lower than those of most of the reported absorbers. Our results highlight the importance of 3D structures composed of graphene and nitrogen-doped carbon nanotubes to high-efficiency EMW absorption.

Lithium–sulfur (Li–S) batteries have been recognized as promising substitutes for current energy-storage technologies owing to their exceptional advantages in very high-energy density and excellent material sustainability. The cathode with high sulfur areal loading is vital for the practical applications of Li–S batteries with very high energy density. However, the high sulfur loading in an electrode results in poor rate and cycling performances of batteries in most cases. Herein, we used diameters of 5.0 (D5) and 13.0 (D13) mm to probe the effect of electrodes with different sizes on the rate and cycling performances under a high sulfur loading (4.5 mg cm−2). The cell with D5 sulfur cathode exhibits better rate and cycling performances comparing with a large (D13) cathode. Both the high concentration of lithium polysulfides and corrosion of lithium metal anode impede rapid kinetics of sulfur redox reactions, which results in inferior battery performance of the Li–S cell with large diameter cathode. This work highlights the importance of rational matching of the large sulfur cathode with a high areal sulfur loading, carbon modified separators, organic electrolyte, and Li metal anode in a pouch cell, wherein the sulfur redox kinetics and lithium metal protection should be carefully considered under the flooded lithium polysulfide conditions in a working Li–S battery.

Mn-based oxides have sparked extensive scientific interest for aqueous Zn-ion batteries due to the rich abundance, plentiful oxidation states, and high output voltage. However, the further development of Mn-based oxides is severely hindered by the rapid capacity decay during cycling. Herein, a two-step metal-organic framework (MOF)-engaged templating strategy has been developed to rationally synthesize heterostructured Mn

Copper oxide (CuO) electrodes have outstanding potentials for supercapacitors in virtue of their low cost, environment friendly, especially, and the high theoretical specific capacitance (1800 F g−1). However, their poor electronic conductivity restricts the practical application. Doping appropriate transitional metal ions into host materials is an effective method to modulate the electronic structure and improve the conductivity, furthermore, enhancing the energy storage capacity. Herein, Mo-doped CuO nanosheets on Ni foams were obtained by combining a simple hydrothermal process and calcination treatment. Different doping concentrations of Mo were discussed, and the as-prepared 3 at.% Mo-doped CuO (Mo-CuO-2) exhibited the best electrical conductivity and the highest specific capacitance of 1392 F g−1 at 2 A g−1. In addition, an asymmetric supercapacitor device was assembled using Mo-CuO-2 and activated carbon as a positive electrode and a negative electrode, which exhibited a remarkable energy density of 36 Wh kg−1 at 810 W kg−1 and an excellent cycle life with 81% capacitance retention for over 5000 cycles. More significantly, Mo-CuO-2 is a promising material candidate for practical energy storage applications.

Herein, we use reduced graphene oxide as a substrate and NiFe as a catalyst to fabricate three-dimensional (3D) nitrogen-doped carbon nanotube (NCNT)/reduced graphene oxide heteronanostructures (3D NiFe/N-GCTs). The 3D NiFe/N-GCTs are composed of two-dimensional (2D) reduced graphene oxide-supported one-dimensional (1D) NiFe nanoparticle-encapsulated NCNT arrays. The NCNTs exhibit bamboo-like shapes with the length and diameter of 3-10 μm and 15-45 nm, respectively. Besides integration of advantages of 1D and 2D nanomaterials, the 3D NiFe/N-GCT heteronanostructure possesses interconnected network structures, sufficient interfaces, numerous defects, hundreds of void spaces enclosed by bamboo joints and the walls of the NCNT in an individual carbon nanotube, and large surface areas, which can improve their dielectric losses toward electromagnetic wave. Thus, the 3D NiFe/N-GCTs show satisfied property toward electromagnetic wave absorption. Typically, the optimized 3D NiFe/N-GCT displays excellent minimal reflection loss (-40.3 dB) and outstanding efficient absorption bandwidth (4.5 GHz), outperforming most of the reported absorbers. Remarkably, the synthesis of 3D NiFe/N-GCTs only involves vacuum freeze-drying and subsequent thermal treatment process at a high temperature, and thus, the large-scale production of 3D NiFe/N-GCTs can be achieved in each batch, affording the possibility of the practical applications of the 3D NiFe/N-GCTs.

Lithium–sulfur batteries are attracting great attention due to their high theoretical capacity, low cost and environmental friendliness. However, the severe lithium polysulfides shuttling, self-discharge behavior and insulating end redox products (Li2S/Li2S2) remarkably hinder the performance. The cell configuration with an interlayer toward the cathode is an effective strategy to circumvent the above challenges. In this study, a carbon fibers/Ti3C2Tx interlayer is proposed to provide a physical shield and a strong chemical affinity to mitigate the polysulfides shuttling. The 3D cross-linked conductive networks of carbon fibers/Ti3C2Tx interlayers provide fast electron transfer channels and, thus, increase sulfur utilization and save “dead” sulfur. The dual effects of carbon fibers/Ti3C2Tx layers enable the Li–S cells with a high initial discharge capacity of 1380 mAhg−1 at a current density of 0.1 C and an ultralow capacity loss of 0.044% per cycle within 1000 cycles at 1 C. We found that the family of MXenes plays unique roles in immobilizing and converting the polysulfides. The design of a carbon fibers/Ti3C2Tx interlayer with dual effects paves the ways for improving the performance of battery systems that involve complex phase conversion reactions.

The rapid development of the portable and wearable electronics creates a high demand for better performance energy storage devices with high areal capacity as well as excellent flexibility. Herein, a free-standing Ti3C2/FeOOH quantum dots (QDs) hybrid film has been designed and synthesized by a simple electrostatic self-assembly, where amorphous FeOOH QDs not only act as pillars to prevent restacking of the Ti3C2 nanosheets but also provide considerable capacitance as active materials. The Ti3C2/FeOOH QDs hybrid film exhibits 2.3 times higher areal capacitance (485 mF cm−2) than the pristine Ti3C2 film and good cycle stability (94.8% retention over 5000 cycles) in neutral electrolyte. Moreover, an asymmetric device has been prepared by combining the hybrid film as negative electrode and MnO2 on carbon cloth as positive electrode, which operates at an output potential difference of 1.6 V. The device delivers the maximum energy density of 40 μW h cm−2 and the maximum power density of 8.2 mW cm−2 with 82% capacitance retention after 3000 cycles. The facile preparation process and excellent electrochemical properties of the free-standing Ti3C2/FeOOH QDs hybrid film make it a promising candidate for constructing high-performance flexible energy storage devices.

Currently, the detection of hydrogen sulfide is important due to its negative effect on environment and human health. In this paper, the porous MoO3/SnO2 nanoflakes (NFs) with n–n junctions, compos...

Most of metal−organic frameworks (MOFs) themselves have low electrical conductivities, leading to bad electromagnetic wave (EMW) absorption properties. Herein we found that the EMW absorption property of zeolitic imidazolate frameworks-8 (ZIF-8) particles was improved unexpectedly after coupling them with graphene sheets. Experimental results and theoretical calculations indicated that well-defined interfaces between ZIF-8 and the graphene sheets were crucial to the improvement of EMW absorption property. Our strategy presented here may open a new way for designing other MOFs based hybrids for high-performance EMW absorbers.

Hydrogen sulfide even with low concentration in environment is very pernicious to the health, Therefore, the design of gas sensors for detecting H2S is highly desirable. In this work, porous spinel ZnCo2O4 nanosheets (NSs) were synthesized via a hydrothermal method and followed by the thermal treatment. Structural characterizations indicate that the porous NSs are composed of ~ 14 nm interconnected ZnCo2O4 nanoparticles. The porous spinel ZnCo2O4 NSs exhibit enhanced H2S sensing performance in comparison to Co3O4 NSs. The detection limit of the porous ZnCo2O4 NSs is down to 100 ppb H2S with a sensor response value of 1.32 even at relatively low operating temperature of 120 °C. Furthermore, the porous ZnCo2O4 NSs have fascinating selectivity and good long-term stability and relatively rapid response time. The gas sensing mechanism of the ZnCo2O4 NSs gas sensor is also discussed in terms of the effects of oxygen vacancies. In view of the exciting gas-sensing properties and facile preparation method, the porous ZnCo2O4 NSs are ideal candidates for the H2S sensors.

To solve the restacking of the Ti3C2Tx nanosheets and destroy of electrode microstructure during cycles and gain high-performance electrode for supercapacitors, Ti3C2Tx/PDA composite film electrode was rationally designed and successfully synthesized by one-step in situ polymerization of dopamine on the surface of the Ti3C2Tx nanosheets. The as-synthesized Ti3C2Tx/PDA composite electrode achieved a superior areal capacitance of 715 mF/cm2 at a scan rate of 2 mV/s and maintained 95.5% of initial capacitance after 10000 cycles, exhibiting long-term cycling stability. The areal capacitance can be enhanced to 3440 mF/cm2 when the mass loading increases to 13.6 mg/cm2. The improved electrochemical performance and outstanding electrochemical stability can be attributed to the effective suppressing the restacking of Ti3C2Tx sheets and increasing interlayer spacing by introducing PDA, which could be beneficial to expose more surface active sites, shorten the diffusion path of electrolyte ions, promote electron transport and fast Faradaic reaction. Our work opens new design space to develop the high performance negative electrode materials.

Superstructure design of a single-layer MoS2/C/Ti3C2Tx@C composite electrode is reported. Application of the composite materials as high performance electrode for lithium ion batteries is investigated. The composite materials are comprised of the SL-MoS2/C superstructure and Ti3C2Tx@C core-shell structure. The SL-MoS2/C superstructure with a nanoscopic/atomic interface could efficiently prevent undesirable surface reactions between the active materials and electrolyte. The cycling performance of active MoS2 can be greatly improved due to the incorporation of superstructure. The SL-MoS2/C/Ti3C2Tx@C composite electrode shows an ultralong cycle life and delivers a discharge capacity of 962 mAh g−1 at the current density of 0.1 A g−1. A high reversible capacity of 875 mAh g−1 is retained even after 1500 cycles at the current density of 1.0 A g−1.

The high intercalation capacitance of MXenes is attractive, but their performance as electrodes in supercapacitors is limited by mass transport when increasing the thickness and mass loading of the electrodes. Here, we report a combined experimental and computational study, through which we reveal the diffusion of hydrated ionic species at the interlayer spaces. We find that the cyclic voltammetry (CV) curves for the delaminated Ti3C2T x exhibit distinct features in acid (H2SO4) and alkaline (KOH) electrolytes. The calculated migration profiles of K+ and H+ using density functional theory, in the presence and absence of water, suggest that the intercalated water molecules stabilize the charged ions, facilitating their diffusion from two dimension to three dimension manifested by reduced activation barriers and movement pathways. In addition, we show that the diffusion of low and high concentrations of protons is significantly different; that is, protons of high concentrations can be adsorbed at both sides of the interlayer spaces, and water drives frequent proton hopping between stable adsorption sites as shown in the ab initio molecular dynamics simulations. The calculations can thus explain the varied capacitance and distorted CV curves when the experiments are conducted in acid and alkaline electrolytes. These results can provide guidance for improving the fast transport of ions and electrons in MXenes with high mass loading.

MXenes are two-dimensional transition metal carbides/nitrides, and they have shown exciting application prospects for electrochemical energy storage in the future owing to their hydrophilicity, metallic conductivity and surface redox reactions, which are crucial for high-capacitance and high-rate electrode materials. However, the strong tendency of adjacent MXene flakes to aggregate or self-restack under the van der Waals force limits the electrochemical performance of MXene-based electrodes for practical applications. In this study, we developed a simple and effective method to prepare Ti3C2Tx/PEDOT:PSS hybrid films via filtering the Ti3C2Tx/Clevios PH1000 compound inks, followed by H2SO4 treatment. H2SO4 treatment could remove part of the insulating PSS from the Ti3C2Tx/PEDOT:PSS hybrid film, resulting in significant conductivity enhancement of the composite. Furthermore, the conductive PEDOT not only acted as a pillar between Ti3C2Tx sheets to expose more electroactive surfaces and reduce ion diffusion pathways but also played a role as a conductive bridge to form multidimensional electronic transport channels for accelerating the electrochemical reaction process. As a result, the as-prepared H2SO4-treated Ti3C2Tx/PEDOT:PSS (Ti3C2Tx/P-100-H) hybrid film exhibited 4.5-fold increase in the specific surface area and high volumetric capacitance of 1065 F cm-3 at 2 mV s-1 with superior rate performance in 1 M H2SO4 electrolyte. Especially, we assembled an asymmetric supercapacitor (ASC) with excellent flexibility based on a Ti3C2Tx/P-100-H hybrid negative electrode and rGO film positive electrode, which delivered high energy density of 23 mW h cm-3 and high power density of 7659 mW cm-3. Moreover, a simple luminous band was designed and powered by our two ASCs in series. The outstanding volumetric electrochemical performance and energy density of the ASC based on the flexible Ti3C2Tx/P-100-H hybrid film electrode demonstrated its promising potential as a strong power source for small portable and wearable electronic devices.

High-performance multi-functional electrocatalysts are highly desirable for various energy storage and conversion devices. In this study, we report a one dimensional N-doped carbon nanostructure, containing Mo2C and Co nanoparticles encapsulated in nitrogen-doped graphene layers (Mo2C@NC/Co@NG) as a multi-functional electrocatalyst. The optimized Mo2C@NC/Co@NG exhibited high activities and stabilities towards oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The experimental results demonstrate that the high activities and stabilities of the multi-functional catalysts are ascribed to the synergistic effect between Mo2C, Co, and N dopants. Typically, the optimized Mo2C@NC/Co@NG catalyst delivered a HER current density of 10 mA cm−2 at a small overpotential of 142 mV. Furthermore, a rechargeable zinc–air battery with the optimized Mo2C@NC/Co@NG as OER and ORR bifunctional catalyst showed a high round-trip efficiency and robust cycling stability, superior to the battery assembled with the benchmarked mixture of Pt/C and IrO2 as the air electrode. This study provides a simple method to reasonably design and fabricate highly efficient and stable multi-functional catalysts for clean and sustainable energy storage and conversion devices.

Zinc–air batteries and full water-splitting devices, as environmentally friendly electrochemical energy storage and conversion systems, have drawn extensive attention. However, effective, low-cost and durable electrochemical catalysts for the involved oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are highly desired. Herein, a new N, B co-doped Co3C multifunctional catalyst with enhanced ORR, OER and HER activities, as well as improved ORR and OER stabilities, in alkaline media has been synthesized. The strategy used, immersing N-doped Co3C in NaBH4 solution, not only achieves N, B co-doping via the N anchoring effect to B at room temperature for the first time, but also engineers the outmost surface of Co3C-N by forming nanosheet arrays. Besides, Co–Nx–B and N–B bonds have been successful produced via the anchoring effect of N during the immersion treatment, which is proved by the X-ray photoelectron spectroscopy (XPS) results. In particular, both liquid and solid-state Zn–air batteries that are equipped with Co3C-NB as air-cathodes all exhibit superior cycling stabilities over those with Co3C, N-doped Co3C and Pt/C + IrO2 air-cathodes. Furthermore, a Co3C-NB-based full water splitting device can be successfully driven using two solid-state zinc–air batteries with a Co3C-NB air-cathode in series.

High-performance multifunctional catalysts are very important to various energy conversion and storage devices. FeNi bimetal electrocatalysts have been reported to have good activities toward the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), but negligible oxygen reduction reaction (ORR) activity. Herein, we report an advanced multifunctional electrocatalyst based on 7.6 nm FeNi3N nanoparticles anchored on N-doped graphene (FeNi3N/NG). The as-prepared FeNi3N/NG exhibits not only excellent OER and HER activities, but also unprecedented ORR activity in alkaline media. The density functional theory (DFT) calculations demonstrate that FeNi3N with an active (110) surface has stronger capability for O2 adsorption and cleavage of the O–O bond than Ni4N, leading to significantly enhanced ORR activity of the FeNi3N nanoparticles. As a result, the specific capacity of the primary FeNi3N/NG-based Zn–air battery is as high as 785.2 mA h g−1 at 10 mA cm−2, higher than that assembled with a benchmarked Pt/C + IrO2 catalyst. Besides, the overall water splitting device with the FeNi3N/NG electrode material delivers 20 mA cm−2 at 1.585 V, outperforming electrolyzers assembled with the state-of-the-art bifunctional catalysts. Our results highlight the importance of the fabrication of ultrasmall-sized electrocatalysts with an exposed active surface to the development of renewable energy conversion and storage devices.

Lithium–sulfur (Li–S) batteries with a high theoretical energy density based on multi-electron redox reactions were strongly considered. The lithium disulfide/sulfide (Li2S2/Li2S, denoted as Li2S1/2) precipitation is critical to achieve high sulfur utilization. However, the kinetic effect on Li2S1/2 precipitation in a working battery has been rarely investigated. Herein, the current-density-dependent Li2S1/2 nucleation/growth was explored and such a dependence served as the guiding principle for the construction of high-sulfur-loading/content Li–S batteries. Generally, the Li2S1/2 nucleation density is proportional to two-third the power of the current density and the shift from a high to low current density alters the Li2S1/2 precipitation pathway from surface deposition to solution-mediated growth. The in-solution growth rate was found to be restricted by the mobilities of polysulfide intermediates and Li2S1/2 in conventional ether electrolytes. The rationalized guideline directed the design of a lightweight, high-surface-area, and open-pore conductive framework for sulfur cathodes, which enabled an extremely high sulfur content of 93.4 wt% in the whole electrode and a high capacity (1269 mA h g−1). The present work affords a kinetic understanding of the liquid–solid conversion in working Li–S batteries and optimization schemes for practical operation parameters.

In this work, we use a metal–organic framework and layered double hydroxide nanosheets as precursors to grow transition-metal nanoparticle-encapsulated nitrogen-doped carbon nanotubes on ultrathin graphene sheets. The as-fabricated samples exhibit three-dimensional structures with high electrical conductivities, abundant defects, multiple interfaces and nitrogen dopants. As applied for the attenuation of electromagnetic energy, the optimized 3D architecture with CoNi bimetal nanoparticles exhibits excellent attenuation properties of electromagnetic energy even at a thin thickness of 1.5 mm and a low filling ratio of 10 wt% in a paraffin matrix, superior to those of single-metal based 3D architectures and most reported materials. The experimental results demonstrate that the dielectric loss and the impedance matching characteristic can be modulated by adjusting metal compositions, which are responsible for the difference of the 3D architectures in EME attenuation properties. Our strategy opens a new way for lightweight materials for the attenuation of electromagnetic energy.

The understanding of the relationships between the coordination configuration of single-atoms (SAs) and their properties remains a great challenge. In this manuscript, a facile method is developed to construct Fe-SAs on onion-like nitrogen-doped nanocarbons supported by graphene (ONCG). In contrast to the symmetrical planar Fe–N4 moieties, the Fe-SAs coordinated with N atoms are located above the plane of the curved graphene and exhibited antenna-like structures. The ONCG with non-planar Fe–N4 moieties possesses greatly increased dielectric loss property compared to their counterparts with symmetrical planar Fe-SAs. In-depth theoretical calculations reveal that the unique geometric structure of the non-planar Fe-SAs improves both conduction and polarization losses significantly, which is attributed to the increased dielectric property. The increased dielectric property endows Fe-SAs@ONCG with an excellent electromagnetic wave absorption at a low filler ratio of 10 wt. %. Our results describe an efficient way for the development of non-planar SAs for dielectric applications.

Nitrogen-doped carbon sheets containing Fe 3 C nanoparticles encapsulated in nitrogen-doped graphene shells are fabricated through heating the mixture of urea and ferric acetylacetonate and the subsequent treatment in hot acid solution. The nitrogen-doped carbon sheets have a lateral length ranging from hundred nanometers to several micrometers, while the Fe 3 C nanoparticles encapsulated in nitrogen-doped graphene have a diameter of approximately 60 nm. The nitrogen-doped carbon sheets exhibit excellent electromagnetic wave absorption property. Typically, the optimal sample has the effective absorption bandwidth of 6.0 GHz at the absorber thicknesses of only 2.0 mm, favorably comparable to those of the magnetic absorbers reported previously. The excellent electromagnetic wave absorption property of nitrogen-doped carbon sheets containing Fe 3 C nanocapsules encapsulated in the nitrogen-doped graphene shells can be explained by their better impedance matching character and enhanced dielectric loss.

Ordered porous carbon materials (PCMs) have potential applications in various fields due to their low mass densities and porous features. However, it yet remains extremely challenging to construct PCMs with multifunctionalization for electromagnetic wave absorption. Herein, the honeycombed-like carbon aerogels with embedded Co@C nanoparticles are fabricated by a directionally freeze-casting and carbonization method. The optimized aerogel possesses low density (0.017 g cm-3 ), fire-retardant, robust mechanical performance (compression moduli reach 1411 and 420 kPa in the longitudinal and transverse directions at 80% strain, respectively), and high thermal management (high thermal insulation capability and high-efficiency electrothermal conversion ability). Notably, the optimized aerogel exhibits the excellent electromagnetic wave absorption properties with broad effective absorption bandwidth (13.12-17.14 GHz) and strong absorption (-45.02 dB) at a thickness of only 1.5 mm. Density functional theory calculations and the experimental results demonstrate that the excellent electromagnetic wave absorption properties stem from the synergetic effects among high electrical conductivity, numerous interfaces and dipoles and unique ordered porous structure. Meanwhile, the computer simulation technology (CST) simulation confirms that the multifunctional aerogel can attenuate more electromagnetic energy in a practical environment. This work paves the way for rational design and fabrication of the next-generation electromagnetic wave absorbing materials.

Robust and economical catalysts are imperative to realize the versatile applications of hydrogen. Herein, a 1T-MoS

The application of lithium metal anodes for practical batteries is still impeded by safety issues and low Coulombic efficiency caused mainly by the uncontrollable growth of lithium dendrites. Herein, two types of free-standing nitrogen-doped amorphous Zn-carbon multichannel fibers are synthesized as multifunctional hosts for lithium accommodation. The 3D macroporous structures endow effectively reduced local current density, and the lithiophilic nitrogen-doped carbon and functional Zn nanoparticles serve as preferred deposition sites with low nucleation barriers to guide uniform lithium deposition. As a result, the developed anodes exhibit remarkable electrochemical properties in terms of high Coulombic efficiency for more than 500 cycles at various current densities from 1 to 5 mA cm-2 , and symmetric cells show long-term cycling duration over 2000 h. Moreover, full cells based on the developed anode and a LiFePO4 cathode also demonstrate superior rate capability and stable cycle life. Ministry of Education (MOE) National Research Foundation (NRF) Accepted version X.W.L. acknowledges the funding support from the National Research Foundation (NRF) of Singapore via the NRF investigatorship (NRF-NRFI2016-04), and Ministry of Education of Singapore via the AcRF Tier-1 grant (RG3/20). X.T.Z. acknowledges the funding support from National Natural Science Foundation of China (51772069).

It is highly desirable, but challenging to develop multi-functional electromagnetic wave (EMW) absorbing material for practical applications in some special environments. Herein, we successfully fabricated cobalt-nanoparticle-embedded N-doped carbon nanotube arrays on the carbonized cotton fiber cloth as multifunctional material with an excellent EMW absorption, flexibility, hydrophobicity, and electric-thermal performance. The excellent multifunction benefits from high conductivity, large specific surface area, abundant N dopants, and three-dimensional open porous features. Minimal reflection loss and efficient absorption bandwidth of the optimized material as EMW absorbers can reach −57.8 dB and 4.5 GHz, respectively, which are better than most reported carbon-based absorbers. Meanwhile, theoretical simulations of the radar cross-sectional (RCS) further confirm that the multifunctional material has excellent EMW attenuation performance and potential in practical application. Moreover, the materials possess strong hydrophobicity and high electrical conductivity, endowing them with other attractive functions of self-cleaning and good electric thermal performance, which expand the potential applications range of EMW absorption materials. Our present method can be extended to design next-generation EMW absorbing materials with multifunctionalities for practical applications in harsh environments.

Since EGFR is an important and effective target for tumor therapy in the clinic. Several monoclonal antibodies and nanobodies were proved to target domain III of EGFR. Regarding the increased attention on nanobodies, the present study aimed to generate nanobodies specifically against domain III. After camel immunization, a gene repertoire of sdAb fragments with a diversity of 3×109 clones was produced. Following the construction of two sdAb phage display libraries, the successful epitope binning was carried out to identify the nanobody with the designated epitope. Modelling of the identified nanobody and molecular docking studies illustrated the paratope and epitope. Docking analysis revealed that the paratope focused on CDR2 loop of the identified nanobody. The identified nanobody potently cover part of the epitope of Matuzumab and Nb 9G8, which indicated that it blocked EGFR by preventing dimerization of the receptors.

Diluted magnetic semiconductors (DMSs) have traditionally been employed to implement spin-based quantum computing and quantum information processing. However, their low Curie temperature is a major hurdle in their use in this field, which creates the necessity for wide bandgap DMSs operating at room temperature. In view of this, a single-electron transistor (SET) with a global back-gate was built using a wide bandgap ZnO nanobelt (NB). Clear Coulomb oscillations were observed at 4.2 K. The periodicity of the Coulomb diamonds indicates that the Coulomb oscillations arise from single quantum dots of uniform size, whereas quasi-periodic Coulomb diamonds correspond to the contribution of multi-dots present in the ZnO NB. By applying an AC signal to the global back-gate across a Coulomb peak with varying frequencies, single-electron pumping was observed; the increase in current was equal to the production of electron charge and frequency. The current accuracy of about 1% for both single- and double-electron pumping was achieved at a high frequency of 25 MHz. This accurate single-electron pumping makes the ZnO NB SET suitable for single-spin injection and detection, which has great potential for applications in quantum information technology.

Additional file 1: Table S1. Binding sites of anti-EGFR antibodies.

Larger-scale usage of the clean energies requires advanced energy storage and conversion techniques. Overall water splitting and zinc air systems are promising energy conversion and storage means, but need high-performance, low-cost, and highly stable bifunctional electrocatalysts to hydrogen evolution/oxygen evolution reactions (HER/OER) and OER/oxygen reduction reactions (ORR), respectively. Herein we develop a facile method to fabricate CoMn double hydroxide (DH) hollow spheres as high-performance trifunctional electrocatalysts for overall water splitting and zinc-air battery. The outmost surfaces of the CoMn DH hollow spheres are composed of ultrathin nanosheets with a thickness of approximately 2.5 nm. Owing to the hollow and ultrathin features, CoMn DH hollow spheres exhibit excellent activities and robust stabilities toward HER, OER, and ORR. The overall water electrolyzer assembled with the CoMn DH hollow spheres can drive a current density of 10 mA cm–2 at an overpotential of merely 420 mV in 1.0...

Electrochemical water splitting is an efficient way for large-scale production of clean hydrogen fuel. However, high overpotential is required to catalyzing oxygen evolution reaction (OER). Here we fabricate self-supported CoMn-LDH nanosheets with a thickness of approximately 1.9 nm on carbon fiber cloth through electrodeposition method within 50 s. The self-supported, binder-free anodes exhibit excellent OER performance with an overpotential of 258 mV at 10 mA cm−2 in 0.1 M KOH solution, remarkably lower than those of Co and Mn single counterparts, and the-state-of-the-art IrO2 catalyst. Furthermore, self-supported, binder-free anodes exhibit robust stability for OER with a negligible current loss even at a high current density (>370 mA cm−2) over 15 h. Flexible and bendable measurements indicate no obvious degradation in the OER performance of the anode even as being bended to 180°. Moreover, the water electrolysis with the CoMn-LDH/CFC as anode and Pt/C/CFC as cathode only needs a cell voltage of 1.54 V to deliver the current density of 10 mA cm−2 in 0.1 M KOH solution. Our experimental results demonstrate that the electron interaction between Mn and Co, increased electrochemical active area and decreased charge-transfer resistance contribute to the enhancement of the optimized anode in OER performance.

To prevent restacking of the Ti 3 C 2 T x layers, the Ti 3 C 2 T x -foam has been successfully synthesized through thermal treatment of Ti 3 C 2 T x -film with the hydrazine monohydrate. The interconnected porous structure of Ti 3 C 2 T x -foam could effectively reduce the restacking of the Ti 3 C 2 T x sheets and shorten the diffusion path of ions and accelerate the intercalation/de-intercalation of ions. The Ti 3 C 2 T x -foam-80 used as free-standing electrode achieves a high areal capacitance of 271.2 mF/cm 2 (122.7 F/g) at a scan rate of 5 mV/s in 1 M KOH electrolyte. It also exhibited a high capability rate of 65.5% from 5 mV/s to 100 mV/s and good cycle life with 88.7% retention of its initial after 10,000 cycles at a scan rate of 50 mV/s.

Magnetic metal nanostructures have exhibited good electromagnetic wave (EMW) absorption properties. However, the surface of the nanostructures is easily oxidized upon exposure to air, leading to the bad stability of the EMW absorption properties. We use metal-organic framework structure as a template to fabricate hollow N-doped carbon polyhedron containing CoNi alloy nanoparticles embedded within N-doped graphene (CoNi@NG-NCPs). The atomic ratio of Co/Ni can be tuned from 1:0.54 to 1:0.91 in the hollow CoNi@NG-NCPs. Experimental results demonstrate that the EMW absorption properties of the CoNi@NG-NCPs can be improved through the Ni introduction and increased with an increase of the Ni content. Typically, the minimal reflection loss of the optimal CoNi@NG-NCP can reach -24.03 dB and the effective absorption bandwidth (reflection loss below -10 dB) is as large as 4.32 GHz at the thickness of 2.5 mm. Furthermore, our CoNi@NG-NCPs exhibit favorably comparable or superior EMW absorption properties to other magnetic absorbers. In addition, because the CoNi alloy nanoparticles are coated with N-doped graphene layers, their surface oxidation behavior can be efficiently limited. The mechanism of the enhanced EMW absorption property is relevant to the enhanced dielectric loss and better impedance matching characteristic caused by the Ni incorporation.